The present invention relates generally to a combustor dome assembly for a gas turbine engine and, in particular, to a combustor dome assembly including swirlers which are contoured to limit stress imposed thereon and so as to allow exposure to cooling holes in an adjacent radial section of a dome plate.
It is well known within the combustor art of gas turbine engines that a dome portion, in conjunction with inner and outer liners, serves to form the boundary of a combustion chamber. A mixture of fuel and air is ignited and burned in such combustion chamber so that the products thereof are able to interface with the blades of turbines and produce work through one or more shafts. The annular combustor dome also serves to position a plurality of mixers in a circumferential manner so that a fuel/air mixture is provided to the combustion chamber in a desired manner.
Gas turbine combustors typically require a floating ferrule or primary swirler to prevent air leakage into the combustor and still allow for thermal growths of the combustor, combustion casing and fuel nozzles. This requirement has oftentimes been accomplished by brazing a secondary swirler or pad into the dome and using a welded retainer to hold the floating ferrule or primary swirler in place. It will be appreciated that the location of such components is critical to the combustor performance and functionality. Examples of such an arrangement are disclosed in U.S. Pat. No. 6,427,435 to Patterson et al. and U.S. Pat. No. 6,314,739 to Howell et al.
While the typical combustor arrangement has adequate space between swirler cups to incorporate features to enhance the spectacle plate structure (e.g., the addition of ribs, cooling holes and the like), certain geometric restrictions have been introduced by current combustor designs which run lean so as to minimize emissions. As disclosed in U.S. Pat. No. 6,381,964 to Pritchard, Jr. et al., one particular fuel/air mixer configuration includes a fuel nozzle containing a pilot mixer therein. The fuel nozzle is then located within a main mixer. Accordingly, the size of the fuel nozzle and the corresponding swirler assembly associated therewith has increased significantly from those previously utilized and thereby reduced the distance between adjacent swirler cups. Utilization of an annular dome having a greater diameter would serve to increase the weight of the engine and require modification of components interfacing therewith. Thus, the openings in the dome plate have been enlarged and thereby lessened the circumferential distance between adjacent openings.
It will be appreciated that a plurality of deflector plates are generally provided in the combustor dome assembly. Such deflector plates are connected to the dome plate adjacent each opening therein in circumferentially spaced relation and protects the dome plate from the extreme effects of the combustion chamber. Cooling for the side edges of the deflector plates is accomplished by means of cooling holes positioned in a radial section of the dome plate between adjacent openings. It will be understood that the swirlers in the combustor dome assembly must be able to prevent leakage of hot gases and allow for thermal growth of the combustor dome assembly.
Thus, in light of the foregoing, it would be desirable for a combustor dome assembly to be developed which accommodates minimum spacing between adjacent swirler cups. It would also be desirable for a swirler to be developed which is configured to perform its intended functions without obstructing cooling flow within the swirler cup.